The unofficial mayor of Brooklyn’s Coney Island is asking the city to hire a condemnation lawyer and take the crumbling Shore Theater away from its negligent owner. Coney Island USA founder Dick Zigun said the owner has been sitting on the property for nearly two decades, leaving it to rot, deteriorating to the point that old mortar is now falling from its facade.

Built in 1925, the ornate building — one of the tallest in Coney Island — hosted major entertainers like Jerry Lewis, but fell to seed in the 1960s and finally closed after a brief stint as an X-rated movie house.

“Whether it’s through the Landmarks Commission or eminent domain, this must be done by any means necessary,” Zigun said during the annual State of Coney Island Address. “The Shore Theater must be occupied.”

Property owner Horace Bullard claims he has tried to get a tenant and will once again put the building on the market in the next six months, but neighborhood activists say they don’t have much faith in Bullard’s words after so many years of inactivity. For this reason, calls for condemnation and eminent domain use have been ringing louder and louder.

Not only is the Shore Theater a landmark in Coney Island, it also sits on prime property next to a subway station at the corner of Surf and Stillwell avenues. Zigan is accusing Bullard of letting his building decay over the years because he’s still angry over two conflicts he had with the city more than 15 years ago, when the Giuliani administration prevented the property holder from recreating Steeplechase Park on city land that’s now home to MCU Park and demolished Bullard’s Thunderbolt roller coaster — a move a federal court later declared illegal. Bullard also fought Zigun’s efforts to have the building landmarked in 2010.

Zigun said he would complain to the city Landmarks Commission about the theater’s poor condition. He’s also considering raising enough money to buy the Shore Theater from Bullard — a move the property owner welcomed.

The theater was once named Loew’s Coney Island Theater, and ran movies and stage shows until the mid-1960s. It was taken over by the Brandt Theater group and renamed the Shore Theater, but its heyday was clearly over and, today, its future remains uncertain.